I’ve spent most of the past week trying to brainstorm entirely hypothetical interactive devices. By this stage, I was hoping to know which children I would be working with – and therefore, what sensory issues I would be focusing on. Unfortunately, due to circumstances out of my control, I’m still waiting to hear from participating families.
This leaves me in a bit of an odd stage of preparation. I’m trying to work on a few different ideas that will allow me to quickly mould them to as many outcomes as possible. The ‘core’ of these devices (common to each) will be the Arduino microcontroller (or compatible), powered via an ethernet shield. The outer form/shell is entirely dependant on the interest(s) of the child, so there’s no point starting that just yet, but there’s a flexible grey area in between that I have been exploring, which I guess will serve as the feedback loop, or interface. Each of these will be modular, thanks to the architecture of the Arduino, so there’s no harm in taking a look at quite a few (aside from the growing cost of this project).
After the Wii components last week, I got my hands on a couple of kits. The first was an RFID module. Using this tutorial (and the components listed in it), setting up the system was a snap. The video below shows some tests to see how the tags are read when they’re not placed parallel to the reader. Mostly, it looks pretty good. Some of them are programmed to give an affirmative read (yellow LED), whilst others are not, and give a negative read (red LED).
What is great about RFID is that each tag has a unique code attached to it. The ones I was using shoot out around 12 integers, which could be assigned to any number of outputs. Amongst other places, it was the SKǺL which excited me about the possibilities when using this within existing objects that the child may already be comfortable with.
Building something that a child rejects – or is simply not interested in – because it’s alien to them, is something I am acutely aware of as being important. I would like to work with whatever the child already enjoys playing with, and try and build upon that experience.
Also arriving in the post this week: the Wave Shield from Adafruit. On its own, Arduino isn’t capable of producing audio much better than that mobile phone you had in 1998, and so it needs a little more power added in the form of the Wave Shield. This shield includes a small digital-to-analogue converter and teeny amp, as well as an SD card reader and 3″ speaker. Adafruit provide really comprehensive guides for putting their kits together, so it was all very straightforward…
…and with the help of the wavehc library, the Wave Shield was spouting all kinds of audio at my mildly annoyed flatmates in no time. What hasn’t worked ‘out of the box’ is using the PoE to power the Arduino + Wave Shield. I haven’t yet had the chance to look into it, but my first guess is that there is some kind of conflict with the pins which power from the Ethernet Shield, and they will need to be reassigned.
Edit: Turns out that my assumption of a pin conflict was correct. It also turns out that this is more of a problem than I first realised: it’s not always a simple case of reassigning pins within the Arduino code. I came across this excellent resource when trying to understand what was going on and spotted that the Wave Shield and Ethernet Shield do use several of the same pins (that means a ‘conflict’ for those playing at home). After looking at the datasheet for each respective device, I found that pin 13 cannot be reassigned for either shield. The moral of the story is to check datasheets *before* buying shields …lesson learned. All is not lost though: by using the Freetronics EtherTen, and removing the need for an additional ethernet shield, I should still be able to power the Wave Shield by PoE.
This coming week really feels like a tipping point in the semester. I need to put my head down and get quite a lot of work done, but mostly I’m sweating on getting confirmation as to the participants I will be working with for the rest of the year. Having this process drag out for longer than expected, I am a little behind where I would have hoped, but still haven’t reached the Land Of Mad Panic just yet.